<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Loader
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Loader.php 16206 2009-06-21 19:15:37Z thomas $
 */

/**
 * Static methods for loading classes and files.
 *
 * @category   Zend
 * @package    Zend_Loader
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Loader
{
	/**
	 * Loads a class from a PHP file.  The filename must be formatted
	 * as "$class.php".
	 *
	 * If $dirs is a string or an array, it will search the directories
	 * in the order supplied, and attempt to load the first matching file.
	 *
	 * If $dirs is null, it will split the class name at underscores to
	 * generate a path hierarchy (e.g., "Zend_Example_Class" will map
	 * to "Zend/Example/Class.php").
	 *
	 * If the file was not found in the $dirs, or if no $dirs were specified,
	 * it will attempt to load it from PHP's include_path.
	 *
	 * @param string $class      - The full class name of a Zend component.
	 * @param string|array $dirs - OPTIONAL Either a path or an array of paths
	 *                             to search.
	 * @return void
	 * @throws Zend_Exception
	 */
	public static function loadClass($class, $dirs = null)
	{
		if (class_exists($class, false) || interface_exists($class, false)) {
			return;
		}

		if ((null !== $dirs) && !is_string($dirs) && !is_array($dirs)) {
			require_once 'Zend/Exception.php';
			throw new Zend_Exception('Directory argument must be a string or an array');
		}

		// autodiscover the path from the class name
		$file = str_replace('_', DIRECTORY_SEPARATOR, $class) . '.php';
		if (!empty($dirs)) {
			// use the autodiscovered path
			$dirPath = dirname($file);
			if (is_string($dirs)) {
				$dirs = explode(PATH_SEPARATOR, $dirs);
			}
			foreach ($dirs as $key => $dir) {
				if ($dir == '.') {
					$dirs[$key] = $dirPath;
				} else {
					$dir = rtrim($dir, '\\/');
					$dirs[$key] = $dir . DIRECTORY_SEPARATOR . $dirPath;
				}
			}
			$file = basename($file);
			self::loadFile($file, $dirs, true);
		} else {
			self::_securityCheck($file);
			include $file;
		}

		if (!class_exists($class, false) && !interface_exists($class, false)) {
			require_once 'Zend/Exception.php';
			throw new Zend_Exception("File \"$file\" does not exist or class \"$class\" was not found in the file");
		}
	}

	/**
	 * Loads a PHP file.  This is a wrapper for PHP's include() function.
	 *
	 * $filename must be the complete filename, including any
	 * extension such as ".php".  Note that a security check is performed that
	 * does not permit extended characters in the filename.  This method is
	 * intended for loading Zend Framework files.
	 *
	 * If $dirs is a string or an array, it will search the directories
	 * in the order supplied, and attempt to load the first matching file.
	 *
	 * If the file was not found in the $dirs, or if no $dirs were specified,
	 * it will attempt to load it from PHP's include_path.
	 *
	 * If $once is TRUE, it will use include_once() instead of include().
	 *
	 * @param  string        $filename
	 * @param  string|array  $dirs - OPTIONAL either a path or array of paths
	 *                       to search.
	 * @param  boolean       $once
	 * @return boolean
	 * @throws Zend_Exception
	 */
	public static function loadFile($filename, $dirs = null, $once = false)
	{
		self::_securityCheck($filename);

		/**
		 * Search in provided directories, as well as include_path
		 */
		$incPath = false;
		if (!empty($dirs) && (is_array($dirs) || is_string($dirs))) {
			if (is_array($dirs)) {
				$dirs = implode(PATH_SEPARATOR, $dirs);
			}
			$incPath = get_include_path();
			set_include_path($dirs . PATH_SEPARATOR . $incPath);
		}

		/**
		 * Try finding for the plain filename in the include_path.
		 */
		if ($once) {
			include_once $filename;
		} else {
			include $filename;
		}

		/**
		 * If searching in directories, reset include_path
		 */
		if ($incPath) {
			set_include_path($incPath);
		}

		return true;
	}

	/**
	 * Returns TRUE if the $filename is readable, or FALSE otherwise.
	 * This function uses the PHP include_path, where PHP's is_readable()
	 * does not.
	 *
	 * Note from ZF-2900:
	 * If you use custom error handler, please check whether return value
	 *  from error_reporting() is zero or not.
	 * At mark of fopen() can not suppress warning if the handler is used.
	 *
	 * @param string   $filename
	 * @return boolean
	 */
	public static function isReadable($filename)
	{
		if (!$fh = @fopen($filename, 'r', true)) {
			return false;
		}
		@fclose($fh);
		return true;
	}

	/**
	 * spl_autoload() suitable implementation for supporting class autoloading.
	 *
	 * Attach to spl_autoload() using the following:
	 * <code>
	 * spl_autoload_register(array('Zend_Loader', 'autoload'));
	 * </code>
	 *
	 * @deprecated Since 1.8.0
	 * @param  string $class
	 * @return string|false Class name on success; false on failure
	 */
	public static function autoload($class)
	{
		trigger_error(__CLASS__ . '::' . __METHOD__ . ' is deprecated as of 1.8.0 and will be removed with 2.0.0; use Zend_Loader_Autoloader instead', E_USER_NOTICE);
		try {
			@self::loadClass($class);
			return $class;
		} catch (Exception $e) {
			return false;
		}
	}

	/**
	 * Register {@link autoload()} with spl_autoload()
	 *
	 * @deprecated Since 1.8.0
	 * @param string $class (optional)
	 * @param boolean $enabled (optional)
	 * @return void
	 * @throws Zend_Exception if spl_autoload() is not found
	 * or if the specified class does not have an autoload() method.
	 */
	public static function registerAutoload($class = 'Zend_Loader', $enabled = true)
	{
		trigger_error(__CLASS__ . '::' . __METHOD__ . ' is deprecated as of 1.8.0 and will be removed with 2.0.0; use Zend_Loader_Autoloader instead', E_USER_NOTICE);
		require_once 'Zend/Loader/Autoloader.php';
		$autoloader = Zend_Loader_Autoloader::getInstance();
		$autoloader->setFallbackAutoloader(true);

		if ('Zend_Loader' != $class) {
			self::loadClass($class);
			$methods = get_class_methods($class);
			if (!in_array('autoload', (array) $methods)) {
				require_once 'Zend/Exception.php';
				throw new Zend_Exception("The class \"$class\" does not have an autoload() method");
			}

			$callback = array($class, 'autoload');

			if ($enabled) {
				$autoloader->pushAutoloader($callback);
			} else {
				$autoloader->removeAutoloader($callback);
			}
		}
	}

	/**
	 * Ensure that filename does not contain exploits
	 *
	 * @param  string $filename
	 * @return void
	 * @throws Zend_Exception
	 */
	protected static function _securityCheck($filename)
	{
		/**
		 * Security check
		 */
		if (preg_match('/[^a-z0-9\\/\\\\_.:-]/i', $filename)) {
			require_once 'Zend/Exception.php';
			throw new Zend_Exception('Security check: Illegal character in filename');
		}
	}

	/**
	 * Attempt to include() the file.
	 *
	 * include() is not prefixed with the @ operator because if
	 * the file is loaded and contains a parse error, execution
	 * will halt silently and this is difficult to debug.
	 *
	 * Always set display_errors = Off on production servers!
	 *
	 * @param  string  $filespec
	 * @param  boolean $once
	 * @return boolean
	 * @deprecated Since 1.5.0; use loadFile() instead
	 */
	protected static function _includeFile($filespec, $once = false)
	{
		if ($once) {
			return include_once $filespec;
		} else {
			return include $filespec ;
		}
	}
}
